Chemical nickel plating methods and apparatus



United States Patent 0 CHEMICAL NICKEL PLATI-NG METHODS AND APPARATUS Paul Talmey, Barrington, and William J. Crehan, Hinsdale, Ill., assignorsto General American Transportation. Corporation, Chicago, Ill'., a corporation of New York Application July 19, 1952', Serial No. 299,784

39 Claims. (Cl. 11797) The present invention relates to chemical nickel plating methods and apparatus; and it is the general object. of the present invention to provide a system and. apparatus and method for carrying out the chemical nickel plating process disclosed in'the copending application of Paul Talmey and William I. Crehan, Serial No. 222,222, filed April 21,

due to the total absence of any known method or apparatus for the satisfactory electrolytic nickel plating. of the large interior surfaces embodied in such containers.

Thus, another object of the present invention is to provide a method of and apparatus for producing a shipping or storage container or tank that comprises an outer body formed essentially of steel sheet, or the like, and a smooth and continuous and substantially homogeneous liner intimately bonded to the interior surface of the body and essentially consisting of a relatively thin layer of noncorrosive metal composed fundamentally of nickel.

Another object of the invention is to provide a method of and apparatus for producing a tank. of the character described, wherein the liner thereof consists essentially of an. alloy of nickel and phosphorus, the alloy contain.- ing. about 3% to 11% phosphorus by weight.

Another object of the invention is to provide a method and apparatus of' the character noted that utilizes a chemical nickel plating process employing achemical nickel platingsolution of the nickelcation-hypophosphite anion type..

A further object of the invention is to provide a methcc! of chemical nickel plating, employing an aqueous chemicallnickel. plating solution of the nickel cation-hypophosplu'te anion type, wherein a first portion of the solution is stored at a relatively low temperature Well below the boiling point thereof in a reservoir, a second portion of the solution is held as a-bath at a relatively high temperature slightly below the boiling, point thereof in a plating chamber, the solution is circulated from the reservoir to the plating chamber and then back to the reservoir, the solution is heated after withdrawal thereof from the reservoir and before introduction thereof into the plating chamber by injecting live steam thereinto, and the solution is cooled after withdrawal thereof from the plating chamber and before return thereof into. the reservoir by effecting. evaporation of water vapor therefrom under subatmospheric pressure.

Afurther object of the invention is to provide a method of the character described, wherein the solution stored in the reservoir is in relatively concentrated form, and the solution held as a bath. in the plating chamber isin relatively dilute form, and wherein the injection of the 2,7 1 ?,Z 18 Patented Sept. 6, 1 955 ice live steam into the solution after withdrawal thereof from the reservoir and before introduction thereof into the plating chamber also effects the desired dilution of the solution, and the evaporation of the water vapor from the solution after withdrawal thereof from the plating chamber and before return thereof into the reservoir effects the desired concentration of the solution.

A further object of the invention is to provide a system for carrying out the method noted in a simple and efficient manner.

A. further object of the invention is to provide a method and apparatus for carrying out the chemical nickelplating of the interior of a shipping container or storage tank.

A further object of the invention is to provide an improved apparatus for carrying out the chemical: nickel plating of the interior of a tank or railway tank car,

wherein the tank is supported exteriorly and rotated during. the plating of the interior thereof upon its support about its longitudinal axis disposed in a substantially horizontal position in order to insure the production of asmooth and continuous and substantially homogeneous lining intimately bonded to the interior surface thereof. A still further object of the invention is to provide improved apparatus for carrying out the chemical nickel plating of the interior of a large shipping or storage container or tank in a simple and efficient manner permitting the commercial production of such tanks.

Further features of the invention pertain to the particular arrangement of the elements of the chemical nickel plating system and apparatus, and of the steps of the method, whereby the above-outlined and additional operating features thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the. following specification taken in. connection with the accompanying drawings, in which Figures 1 and 2, taken together, are a diagrammatic illustration of a system and apparatus forehemical nickel plating the interiors of containers or tanks, embodying the present invention, and in which the method of the present invention may be carried out; and

, Fig. 3 is an enlarged fragmentary sectional view of a portion of a container or tank produced in accordance with the method of the present invention.

In order to form a unified diagram of. the chemical nickel plating system, Fig. 1' should be placed in a vertical position on the left and Fig. 2 should be placed in a horizontal position on the right.

Referring first to Figs. 2 and 3 of the drawings, the railway tank car 10 there illustrated and produced in accordance with the method of the present invention comprises a substantially horizontal outer body 11 including a number of substantially cylindrical sections 12, 13,. 14 and 15, two convex ends or heads 16 and 17, and an upstanding substantially cylindrical and centrally disposed throat 18' that is provided with a removable cover 19 detachably secured in place in liquid-tight relation with theupper end thereof by a series of bolts, or the like, not shown. The meeting edges of the several parts 12 to 18, inclusive, of the body 11, are appropriately secured to- 'gether in liquid-tight relation, as by Welding. Specifically, as illustrated in Fig. 3, the adjacent sections 14 and 15 are secured. together by the welding head 20. The parts 12, etc., of the body 11 are preferably formed of sheet or plate steel in the usual manner; and the welding beads 20', etc., are formed of welding rods consisting essentially of steel. Further, the tank 10 comprises a smooth continuous substantially homogeneous liner 21 intimately bonded to the interior surface of the body 11 andnormally having a thickness in the approximate range of 1 to 5 mils and consisting essentially of an alloy of nickel and phosphorus, the alloy being composed of about 89% to 97% nickel and 11% to 3% phosphorus by Weight. Finally, the tank comprises suitable fill and drain fixtures, not shown, that are also formed essentially of steel and provided with linings of the alloy mentioned. Accordingly, the entire interior of the tank 10 is lined with the noncorrosive liner described so that every element thereof in contact with the fluid to be shipped or stored is coated with the alloy. Of course, it will be understood that the tank 10 is admirably suited to the shipment of various and sundry fluids comprising foods, chemicals, etc., that would normally etch the steel body 11, or would, on the other hand, be contaminated by contact with the steel body 11. However, the noncorrosive alloy mentioned as forming the liner 21 is neither etched by a wide variety of the fluids noted, nor are the fluids contaminated by contact with the lining 21', whereby the tank 10 is useful in the shipment and storage of a wide variety of fluids that cannot be contained in an ordinary steel tank.

The structure of the tank 10, described above, is disclosed in the copending application of Paul Talmey and William J. Crehan, Ser. No. 514,588, filed June 10, 1955, that comprises a continuation'in-part of the present application.

Turning now to Figs. 1 and 2 of the drawings, the chemical nickel plating system there illustrated and embodying the features of the present invention is employed in the production of the interior lining 21 for the body 11 of the tank 10, of the composition previously described, in accordance with the present method; and essentially comprises a pair of longitudinally spaced-apart roller mechanisms 22 and 23 removably receiving and supporting the tank 10 for rotation about its longitudinal axis disposed in a substantially horizontal position. Specifically, the longitudinal axis of the tank 10, indicated by the broken line 24, is disposed at a slight angle with respect to the horizontal, indicated by the broken line 25, the right-hand end of the tank 10 being slightly lower than the left-hand end thereof. Also, the system comprises a thrust roller mechanism 26 engaging the lower right-hand convex head 17 of the tank 10, as well as an electric motor 27 for driving the roller mechanism 23. Thus it will be understood that when the electric motor drive 27 is operated, the roller mechanism 23 supports and'drives by friction the right-hand end of the tank 10;

the roller mechanism 22 supports the left-hand end of the tank 10; and the thrust roller mechanism 26 engages the right-hand head 17 in order to prevent longitudinal displacement of the tank 10 as it is rotated about its longitudinal axis 24. Accordingly, the mechanism 22 comprises idler rolls; the mechanism 23 comprises drive rollers; and the mechanism 26 comprises thrust rollers. Moreover, in the arrangement, the various rollers of the mechanisms 22, 23 and 26 may be appropriately covered with rubber, or the like, to prevent undue noise in operation and to afford a better frictional grip upon the exterior surfaces of the tank 10.

The left-hand head 16 is provided with a fluid-tight fixture 28, including relatively rotative and stationary parts 29 and 30, the rotative part 29 being secured in liquid-tight relation with respect to an opening provided in the head 16 adjacent to the center thereof, and the stationary part 30 being suitably supported by the base or floor, indicated at 31. Similarly the right-hand head 17 is provided with a fluid-tight fixture 32, including relatively rotative and stationary parts 33 and 34, the rotative part 33 being secured in liquid-tight relation with respect to an opening provided in the head 17 adjacent to the center thereof, and the stationary part 34 being suitably supported by the base 31. Further, the system comprises a reservoir 35, including a storage compartment 36 and a communicating regeneration compartment 37. The bottom wall of the storage compartment 36 is provided with a drain conduit 38 arranged adjacent to the lowermost portion thereof that is controlled by a manually operable valve 39; and,

likewise, the bottom wail of the compartment 37 is provided with a drain conduit 40 arranged adjacent to the lowermost portion thereof that is controlled by a manually operable valve 41. The communication between the compartments 36 and 37 is preferably somewhat above the respective bottom walls thereof, as indicated at 42; a series of diffusion baffies 43 are arranged in the storage compartment 36; and a series of mixers or agitators 44 are arranged in the regeneration compartment 37 and carried by a drive shaft 45 that is operated by a suitable electric motor 46. The reservoir 35, as a whole, is adapted to store the bulk of a quantity of aqueous chemical nickel plating solution of the nickel cation-hypophosphiteanion type; while the tank 10 is adapted to hold, as a bath, a relatively small portion of the solution mentioned; whereby the volume of the reservoir 35 may be approximately 15,000 gallons, and the volume of the tank 10 may be approximately 10,000 gallons.

As disclosed in the Talmey and Crehan application mentioned, a chemical nickel plating solution of the type noted is characterized by stability and a low plating rate at a temperature within a first given range disposed well below the boiling point thereof (a band extending somewhat below about F.) and by instability and a high plating rate at a temperature within a second given range disposed near the boiling point thereof (a band extending somewhat below about 210 F.); the optimum temperature in the first range mentioned being the highest possible temperature compatible with stability of the plating solution, and the optimum temperature in the second range mentioned being the highest temperature compatible with a minimum loss of water through evaporation from the plating solution.

Accordingly, in the present system, the bulk of the solution is stored in the reservoir 35 at a temperature in the first-mentioned range (at about 150 F.); whereas the small portion of the solution is held in the tank 10 at a temperature in the second-mentioned range (at about 210 F.). Moreover, in accordance with the method of the present invention, the stored solution in the reservoir is at a relatively high concentration, while the held solution in the tank is at a relatively low concentration, as explained more fully hereinafter.

The chemical nickel plating solution that is employed may be of any suitable type, such, for example, as that disclosed in the copending application of Gregoire Gutzeit and Abraham Krieg, Serial No. 194,656, filed November 8, 1950, now Patent No. 2,658,841, granted November 10, 1953, or that disclosed in the copending application of Gregoire Gutzeit and Ernest J. Ramirez, Serial No. 204,424, filed January 4, 1951, now- Patent No. 2,658,842, granted November 10, 1953, or that disclosed in U. S. Patent No. 2,532,283, granted on Decemher 5, 1950, to Abner Brenner and Grace E. Riddell. The chemical nickel plating solution, disclosed in the Gutzeit and Krieg application mentioned, essentially comprises an aqueous solution containing nickel cations and hypophosphite anions and a buffer; the ratio between nickel cations and hypophosphite anions, expressed in molar concentrations, being within the range 0.25 to 0.60; the absolute concentration of hypophosphite anions, expressed in mole/liter, being within the range 0.15 to 0.35; the absolute concentration of the buffer being approximately equivalent to two carboxyl groups for every nickel cation that can be deposited; for instance, in the case of sodium acetate, 0.120 mole/liter of acetate anion; and the initial pH of the bath being within the approximate range 4.5 to 5.6. The chemical nickel plating solution disclosed in the Gutzeit and Ramirez application mentioned essentially comprises an aqueous solution containing nickel cations and hypophosphite anions and an exaltant in the form of a simple short chain saturated aliphatic dicarboxylic acid; the ratio being nickel cations and hypophosphite anions, expressed in molar concentrations, being within the range 0.25 to 1.60; the absolute concentration of hypophosphite anions,expressed in mole/liter, being within the range 0.15 to 1.20; the absolute concentration of the exaltant' being approximately equivalent to two carboxyl groups for every nickel cation that can be deposited; for instance, in the case of sodium succinate, 0.05 mole/liter of succinate anion; and the initial pH of the bath being within the approximate range 4.3 to 6.8. In the production of the chemical nickel plating baths of Gutzeit and Krieg and of Gutzeit and Ramirez, the nickel cations may be suitably derived from commercial nickel chloride, and the hypophosphite anions may be suitably derived from commercial sodium hypophosphite.

Further, the system comprises two motor driven pumps 47 and 48, a filter 49, two condensers '50 and '51, two flash tanks 52 and 53, two steam jet vacuum pumps 54 and 55, and a plating tank 56, as well as various communicating conduit structure and auxiliaries, described more fully hereinafter. The lower portion of the storage compartment 36 is connected to a conduit 57 that includes a manually operable valve 58;and the upper portion of the storage compartment 36 is connected to a conduit 59 that includes a manually operable valve 60; and the conduits 57 and 59 are interconnected by a by-pass conduit 61 that includes a manually operable valve 62. The conduits 61 and 57 are connected by a conduit 63, including a manually operable valve 64 and a check valve 65, to the inlet of the pump 47; and, likewise, the conduits 59 and 61 are commonly connected by a conduit 66, including a manually operable valve 67 and a check valve 68, to the inlet of the filter 49. The outlet of the pump 47 is connected by a conduit 69, including a manually operable valve 70, to the inlet of the filter 49; and the outlet of the filter 49 is connected by a conduit 71, including a manually operable valve 72, to the upper portion of the condenser50; Also, a liquid flow measuring device 73, preferably a Rotameter, is operatively connected to the conduit 71by an arrangement, including two manually operable valves 74 and 75, and two check valves 76 and 77, so'that the flow of the solution through the conduit 71 into the condenser 50 may be appropriately metered.

In view of the foregoing, it will be understood that by appropriate manipulation of the valves 58, 6'0, 62 and 64,

the solution may be drawn into the inlet of the pump 47 the solution from the outlet of the pump 47 may be governed. Further, by appropriate manipulation of the valve 4 67 some of the solution from the outlet of thepump 47 may be bypassed around the filter 49 back into the inlet of the pump 47; whereby the pump 47 may be controlled to pump the solution at its full capacity, while permitting a variable amount of the solution to pass through the filter 49. In any case, the solution is withdrawn from the storage compartment 36 by the pump 47 and discharged into the upper portion of the condenser 50; and from the lower portion of the condenser 50, the solution is con ducted via a conduit 78, including a check valve 79, into either or both the tank car 10 and the plating tank 56. More particularly, the conduit 7 9 is connected to the inlet of the plating tank 56 via a manually operable valve 80 and a check valve 31, and is connected to the stationary part 30 of the fixture 28 by a manually operable valve 82 and a check valve 83. Also the solution in the conduit 78 may be conducted back into the regeneration compartment 37 via a conduit 84, including a manually operable valve 85 and a check valve 86; which arrangement .is utilized for a purpose more fully explained hereinafter. Live steam at a pressure of about 125 lbs. per square inch gauge in a steam supply conduit 87 is conducted via a manually operable valve 88 into the jet mechanism of the steam jet vacuum pump 54; water vapor is drawn from into the jet mechanism of the steam jet vacuum pump 54'; and the steam and the'water' vapor from the steam jet vacuum pump 54 are injected via a conduit 90 into the upper portion of the condenser 50. In the operation of the steam jetvacuum pump 54, approximately l500lbs. of steam per hour is conducted through the conduit 87, and approximately 1500 lbs. of water vapor per hour is conducted through the conduit 89, whereby the 3,000'lbs. of steam and water vapor are injected via the conduit 90 into the condenser 50 effecting both heating and dilution of the solution conductedthrough the conduit 71 into the upper portion of the condenser 50; A Specifically, the' solution conducted via the conduit 71 into the upper portion of the condenser 50 has a temperature of about 150 F., and is heated to a temperature of about 210 F., and conducted into the conduit 78, and thence either into the plating tank 56 or into the tank car 10 or into both of the I two last-mentioned containers. Also the rateof flow of the solution in the conduit 71 is about 94 gals. per minute, and the rate of flow of the solution .in the conduit 781's about 100 gals. per minute; whereby it is apparent that the solution from the storage compartment 36 is appropriately diluted in the condenser 50 before .it is conducted into the plating tank 56 or into the tank car 10.

I Also an auxiliary live steam injector 91 is arranged in the lower portion of the condenser 50 and is connected by a by-pass conduit 92 to the steam supply conduit 87, the conduit 92, including a manually operable valve 93 and a check valve 94. Thus, it will be understood that the valve .93 may be suitably manipulated in order to permit a predetermined by-pass of steam from the steam"supply conduit 87 directly via the auxiliary injector91 into the condenser 50. Furthermore, a conduit 95 is arranged in by-passing relation with respect to the conduit 92 between the steam supply conduit 87 and the auxiliary steam injector 91,*which conduit 95 includes two check valves 96 and 97 and a temperature control valve .98. The temperature control valve 98 is connected by a capillary tube 99 to a'temperature control bulb 100 arranged in a casing 101 disposed in theconduit 78; whereby-the temperature of the solution in the conduit 78 governs, through the bulb 100 and the capillary tube 99, the position of the temperature control valve 78 so as to govern thev amount of steam that passes through the temperature control valve 98 and consequently through the by-pass conduit 95 from the steam supply conduit 87 into the auxiliary steam injector 91. The arrangement above described, including. the temperature control valve 98, accommodates automatic adjustment. of the temperature of the solution in the conduit 78 by governingthe total amount oflive steam that is injected thereinto by the auxiliarysteam injector 91 in the condenser 50. i The solution from the outlet of the plating tank 5 6 is conducted via a check valve 102 into aconduit 103; and, likewise, the solution from the tank car 10 is conducted via the fixture 32 and a check valve. 104 into the conduit 103; and the conduit 103 communicates with the upper portion of the flash tank 53. The lower portion of the flash tank 53 is connected to the upper portion. of the flash tank 52 by a conduit 105, including a check valve 106; and the lower portion of the flash tank 52 communicates via a chec-kvalve 107 with a conduit 108 that includes a manually operable valve 109 that, is connected toa conduit 110, including a check valve 111, extending to the inlet of the pump 48. The outlet of the pump 48 is connected to a conduit 112 that includes. a manually operable valve 113; and the. conduits 108 and 112 are interconnected by a by-pass conduit 114 that includesa manually, operable valve 115. Finally, the conduit 112 includes a manually operable valve 116 and two check valves 117 and 118 and communicates with the upper portion of the regeneration compartment 37. Also connected to the conduit 112 is a liquid flow measuring device 119, preferably a Rotameter, by an arrangement, including two manually operable valves 120 and 121 and two check 7 valves 122 and 123, so that the flow of the solution through the conduit 112 back to the regeneration compartment 37 may be metered.

The upper portion of the flash tank 52 is connected to the lower portion of the condenser 51 by a conduit 124, including a manually operable valve 125; the upper portion of the condenser 51 is connected to a cool water supply conduit 126, containing cool water at about 90 F., and including a manually operable valve 127 and a check valve 128; the lower portion of the condenser 51 is connected to a drain conduit 129; and the upper portion of the condenser 51 is connected via a conduit 130 to the jet mechanism of the steam jet vacuum pump 55. Also, the jet mechanism of the steam jet vacuum pump 55 is connected via a manually operable valve 131 to the steam supply conduit 87 and the outlet of the steam jet vacuum pump 55 is discharged through a conduit 132 and a vent fixture 133to the atmosphere.

The solution conducted from the conduit 78 into the plating tank 56 and into the tank car 10 may have a temperature of about 210 F.; and the solution conducted from the plating tank 56 and the tank car 10 into the conduit 103 and thence into the upper portion of the flash tank 53 may have a temperature of approximately 2l0 F. Now the operation of the steam jet vacuum pump 54 draws a partial vacuum in the flash tank 53 via the conduit 89 that may correspond to about 12 to 14" of Hg.

' whereby the subatmosphcric pressure in the flash tank 53 effects evaporation of water vapor from the solution in the flash tank 53 so that it is cooled therein. Cons'equently, the solution conducted from the flash tank 53 may have a temperature of about 180 F., and is, of course, accordingly more concentrated than the solution conducted thereinto, as a consequence of the evaporation of the water vapor therefrom. The solution conducted from the lower portion of the flash tank 53 into the conduit 105 and thence into the upper portion of the flash tank 52 may have a temperature of approximately 180 F., as previously noted. Now the operation of the steam jet vacuum pump 55 and the condenser 51 draw a partial vacuum in the flash tank 52 via the conduit 124 that may correspond; to about 22" of. Hg, whereby the subatmospheric pressure in the flash tank 52 effects evaporation of water vapor from the solution in the flash tank 52 so that it is cooled therein. Consequently, the solution conducted from the flash tank 52 may have a temperature of about 150 F., and is, of course, accordingly more concentrated than the solution conducted thereinto, as a consequence of the evaporation of the water vapor therefrom.

The withdrawal of water vapor from the flash tank 53 and the subsequent injection of this water vapor by the steam jet vacuum pump 54 into the condenser 50 brings about a conversion of heat in the system and ef feels a corresponding concentration of the solution in the flash tank 53, whereas the withdrawal of water vapor from the flash tank 52 and the subsequent discharge thereof from the condenser 51 to the exterior prevents an overall dilution of the solution in the system and effects a corresponding concentration of the solution in the flash tank 52. In the operation of the system; the total amount of steam that is injected into the condenser 50 fromthe steam supply conduit 37 per unit time is substantially equal to the total amount of water vapor withdrawn from the flash tank 52 and discharged by the condenser 51 to the exterior per unit time, so that during continuous operation of the system, there'is no overall and undesired substantial dilution of the solution'or substantial expansion of the total volume thereof provided the exterior heat losses are compensated for or kept to a minimum in accordance" with the foregoing method.

' --In the operation of the system, the plating tank.56 may be employed for the purpose of nickel plating the fittings and other accessories of the tank car 10; whereas the portionof the solution held in the tank car 10 brings about the plating ofthe'liner 21 upon the interior sun face thereof as the tank car 10 is rotated about its longitudinal axis 25 upon the roller mechanisms 22 and 23, in the manner previously explained.

The tank car 10 holds a pool of the solution as a'bath having 'a volume of about 5,000 gallons, since the tank car 10 is retained only about half full of the solution as it is rotated. As the nickel plating reaction proceeds, the solution in the tank car 10 is decomposed bringing about the production of hydrogen gas therein that accumulates in the upper portion thereof. In order to prevent a gas lock in the tank car 10, the fittings 28 and 32 are provided with substantially U-shaped conduits 134 and 135 respectively communicating between the interior of the tank car 10 adjacent to the associated ends thereof and the atmosphere. The conduits 134 and 135 are provided with check valves 136 and 137, respectively, in order to prevent the entry of air into the tank car 10.

As the tank car 10 is continuously rotated upon th roller mechanisms 22 and 23, the pool of solution remains in the lower portion thereof, and the upper portion. of the tank car ltldisposed above the level of the solution therein, indicated by the broken line 25, is wet by a film of the solution so that the nickel plating reaction proceeds upon both the upper and lower portions of the interior surface thereof. Accordingly, the tank car 10 must be rotated at a suitable speed in order to prevent undue dep letion of the film of solution carried by the upper portion of the interior surface thereof; and it has been found that by rotating the tank car 10 at a speed of about 15 R. P. M. the film of solution carried by the upper portion of the interior surface thereof is not depleted by an amount greater than 50%, with respect to the normal consistency of the solution contained in the lower portion of the tank car 10.

Of course, as the plating operation proceeds there is a tendency for the total quantity of solution contained in the system to be depleted somewhat with respect to the normal or standard composition thereohwhereby it is necessary, in order to prevent this tendency, periodically to regenerate the plating solution in the systern by the addition of appropriate reagents in the regeneration compartment 37. More particularly, the reagents are added in the regeneration compartment 37 during operation of the motor 46 so that the mixers 44 quickly place the reagents into solution; and the addition of the reagents is sufliciently frequent so that the composition of the solution does not materially depart from the normal or standard composition previously noted. More specifically, the nickel cations and the hypophosphite anions are depleted during the plating operation, whereby appropriate amounts of commercial nickel chloride and sodium hypophosphite are added periodically in the regeneration compartment 37. Also, as the plating operation proceeds, the acidity of the solution is increased; and in order to prevent the undesirable reduction in the pH thereof, an appropriate weak alkali, such, for example, as commercial sodium bicarbonate is added in the regeneration compartment 37. The arrangement whereby the reagents mentioned are added in the regeneration compartment 37 is very advantageous in view of the fact that the bulk of the plating solution is retained in the communicating regeneration compartment 37 and storage compartment 36, whereby the consistency of the plating solution that is circulated from the storage compartment 36 into the plating tank 56 and into the tank car 10 does not depart appreciably from the normal or standard consistency thereof. This arrangement is very advantageous in view of the circumstance that the retention of the plating solution in the plating tank 56 and in the tank car 10 substantially at the normal or standard consistency thereof prevents stratification of the layer of nickel that is deposited upon the article placed in the plating tank 56 and of the liner 21 that is produced upon the interior surface of the tank car 10. Specifically, the liner 21 is smooth, continuous and substantially homogeneous and totally devoid of stratification or lamination by virtue of the carrying out of the plating. operation employing the plating. solution in such a manner that the consistency, thereof does not depart materially from the normal or standard-consistencyinitially established in the storage compartment 36.

In view of the foregoing description of the plating system, it will be understood that the tank car 10 may be readily placed and removed with respect to the roller mechanisms 22 and 23 by an appropriate overhead crane, not shown, and that the fixtures 28' and 32 are readily connecti-ble and disconnectible with respect to the relatively rotative and stationary partsth ereof to accommodate the placement and removal of the tank car 10. After the tank car 10 has been provided with the lining 21 of the character specified and consisting essentially of the alloy of nickel and phosphorus, about 89% to 97% nickel and 3 to 11% phosphorus by weight, the plating solution contained in the tank car 10 is removed therefrom before removal of the tank car 10 from the roller mechanisms 22 and 23, in the manner noted. Specifically, the tank car 10 is rotated so that the throat 18 is arranged at the bottom and a suitable connection is made via a fitting, not shown, carried by the cover 19 to an associated conduit 138, including a manually operable valve 139. At this time, the pump 48 may be operated, with the valve 139 in its open position and the valve 109 in its. closed position in order to withdraw the plating. solution from the. tank car 10 and to discharge it via the conduit 112 and thence into the. regeneration. compartment 37 for storage therein and in the storage compartment 36. Thereafter the connection between the fixture, not. shown, carried by the cover 19 and the conduit. 13% is disconnected, and the tank car 10 is removed by the overhead crane, not shown, from the roller. mechanisms 22- andv 23, the fixtures 28 and 32 having; been previously set for the removal. of the tank car 101 Of course, it is apparent that. another tank car 10' may be placed upon the roller mechanisms 22 and 23 by the overhead crane, not shown, in a reverse manner, after the relatively rotative parts 29 and 33 of thefixtures. 28 and 32 have been secured in the openings provided in the respective heads 16 and 17 thereof. Following placement of the new tank car 10 upon the roller mechanisms 22 and 23, the fixtures 28 and. 32 are again set for rotation in order to provide fluid-tight connections with respect to the respective cooperating stationary parts and 34 thereof.

When operation of the plating system is first initiated the bulk. of the plating solution stored in the storage compartment 36 and in the regeneration compartment 37 may be substantially below the normal operating temperature of about'150 F., whereby it is thus necessary to bring about an initial warm-up of the plating solution before circulation thereof through the plating tank 56 and the tank car 10. This may be readily accomplished by closing the valves 80- and 82 in order to cut off the circulation of the plating solution through the plating tank 56 and through the. tank car 10 and by opening the valve 85 in order. to accommodate local circulation of the plating solution from the conduit 78 through. the conduit 84 back into the regeneration compartment. 37. During this warm-up period, the plating solution is circulated by the pump 47 through the storage compartment 36, the filter 49 and the condenser 50 and thus into the conduit 79 and back via the conduit 84 into the regeneration compartment 37. In this local circulation of the plating solution, live steam is injected thereinto in the condenser 50. This local circulation is continued until the bulk of the solution is appropriately preheated to the temperature of about 150 F. in the storage compartment 36. Thereafter the valve 85 may be closed and the valves and 82' may be opened in order to bring about circulation of the plating solution through the plating tank 56' and the tank car It), in the manner previously explained.

In the foregoing description of the mode of operation of the plating system in carrying out the present method, the tank car 10' has been described as being formed of steel, which, of course, is the normal case, but it is noted that the tank car 10-may be formed of any suitable catalytic material. Likewise the articles or fixtures that are plated in the plating tank 56 may be formed of steelor any other suitable catalytic material. In this connection, it is noted that the following elements are catalytic and may be readily nickel plated: copper, silver, gold, beryllium, boron, germanium, aluminum, thallium, silicon, carbon, vanadium, molybdenum, tungsten, chromium, selenium, tellurium, titanium, iron, cobalt, nickel, paladium and platinum; whereas the following elements are noncatalytic and may not ordinarily be nickel plated: bismuth, cadmium, tin, lead and manganese. Of the catalytic elements noted, the following are particularly good catalysts in the chemical nickel plating baths mentioned: aluminum, carbon, chromium, cobalt, iron, nickeland palladium. Of course, it will be understood that various and sundry alloys of the catalytic elements mentioned may be readily plated, and that the chemical nickel plating reaction is autocatalytic' so that once it is initiatedit proceeds automatically. Also such nonconductors as vitreous, ceramic and plastic materials, and the like, are noncatalytic and may not ordinarily be nickel plated employing the present method.

While the layer of plating produced upon a catalytic material is composed fundamentally of nickel, the layer is, in fact, an alloy of nickel and phosphorus, as previously noted, which circumstance brings about several advantages in that the alloy is considerably harder than a corresponding pure nickel layer produced by electrode-- position. Furthermore, since the chemical nickel plating reaction of the present method is autocatalytic and the plating solution is manipulated so as to prevent material departure thereof from the normal or standard composition thereof, the chemical nickel plating reaction may becarried on for any suitable length of time in order to obtain the lining 21 in the body 11 of the tank car 10 in any appropriate and desired thickness, although normally a thickness within the range 1 to 5 mils is entirely appropriate for the lining of railway tank cars.

Thus it will be appreciated that a considerable saving is effected by the utilization of the present method since the lining 21 provided upon the interior surface of the body 11 of the tank car 10 is smooth, continuous and substantially homogeneous and has a thickness normally not in excess of about 5 mils. On the other'hand, in the fabrication of railway cars from nickel-clad steel about thethinnest nickel coating that maybe employed has a thickness of about mils, and in the production of such. railway cars employing the nickel-clad steel mentioned, cracks and crevices are formed in the resulting lining that are most objectionable when the railway car is. ultimately placed in use and employed for the'purpose of shipping certain foods, such as milk, wine, or' the like, as it is obvious that the shipped material accumulates in the cracks and crevices mentioned rendering it virtually impossible to clean the tank car after use and before it is again employed in the transportation or storage of other material. On the other hand, the railway car 10 having a smooth, continuous and substantially homoge neous lining 21 produced in accordance with the present method is entirely satisfactory for the shipment of foods of the character mentioned by virtue of the circumstance that the interiorof the lining 21 may be readily andthoroughly cleaned in a simple manner after use since it. is devoid of the cracks and crevices mentioned.

Finally, in the system the interior surfaces of the various tanks 35, 50, etc., the various conduits 71, 78, etc., and the various elements 73, 119, etc., must be appropriately lined with glass, porcelain, plastic material or other nonconductive and noncatalytic substance in order to prevent chemical plating of nickel thereupon in an undesirable manner. 7

In view of the foregoing, it is apparent that there has been provided an improved system and method of chemical nickel plating, as well as an improved method of producing a large shipping or storage container or tank having a smooth and continuous and substantially homogeneous liner formed fundamentally of nickel.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A chemical nickel plating system comprising a res ervoir for storing a first portion of an aqueous chemical nickel plating solution of the nickel cation-hypophosphite anion type at a relatively low temperature, a plating cham her for holding a second portion of said solution as a bath at a relatively high temperature, a condenser, means for conducting said solution from said reservoir into said condenser, means for injecting live steam into said solution in said condenser in order to heat said solution therein, means for conducting said solution from said condenser into said plating chamber, said solution being heated substantially to said relatively high temperature before it is introduced into said plating chamber, a flash tank, means for conducting said solution from said plating chamber into said flash tank, means for withdrawing and discharging to the exterior water vapor from said solution in said flash tank by maintaining a subatmospheric pressure therein in order to cool said solution therein, and means for conducting said solution from said flash tank back into said reservoir, said solution being cooled substantially to said relatively low temperature before it is returned back into said reservoir, the quantityv of said live steam injected into said solution in said condenser and the quantity of said water vapor withdrawn from said solution in said flash tank being substantially equal.

2. A chemical nickel plating system comprising a reservoir for storing a first portion of an aqueous chemical nickel plating solution of the nickel cation-hypophosphite anion type at a relatively low temperature and at a relatively high concentration, a platingchamber for holding a second portion of said solution as a bath at a relatively high temperature and at a relatively low concentration, a condenser, a flash tank, means for circulating said solution from said reservoir into said condenser and then into said plating chamber and then into said flash tank and then back into said reservoir, means for simultaneously heating said solution and for diluting said solution by injecting a controlled amount of live steam thereinto in said condenser, said solution being both heated substantially to said relatively high temperature and diluted substantially to said relatively low concentration before it is introduced into said plating chamber, and means for simultaneously cooling said solution and for concentrat ing said solution by withdrawing and discharging to the exterior water vapor from said solution in said flash tank by maintaining a subatmospheric pressure therein, said solution being both cooled substantially to said relatively low temperature and concentrated substantially to said relatively high concentration before it is returned back into said reservoir.

3. The system set forth in claim 3, wherein said means for simultaneously heating and diluting said solution in said condenser essentially comprises a steam injector.

4. The system set forth in claim 1, wherein-said res- 12 ervoir includes a storage compartment and a communicating regeneration compartment, said solution being conducted from said storage compartment into said condenser and being conducted from said flash tank back into said regeneration compartment, said regeneration compartment accommodating the reception of make-up nickel cations and make-up hypophosphite anions to prevent substantial departure of the composition of said solution from a predetermined standard in said plating chamber as a consequence of a chemical nickel plating reaction taking place therein, and wherein said system further comprises an agitator arranged in said regeneration compartment and operatively associated with said solution therein.

5. The system set forth in claim 1, wherein each of said elements named is lined with a noncatalytic material in order to prevent chemical nickel plating thereon incident in contact thereof with said solution.

6. A chemical nickel plating system comprising a reservoir for storing a first portion of an aqueous chemical nickel plating solution of the nickel cation-hypophosphite anion type at a relatively low temperature, a plating chamber for holding a second portion of said solution as a bath at a relatively high temperature, a condenser, means for conducting said solution from said reservoir into said condenser, a first flash tank, means for conducting said solution from said plating chamber into said first flash tank, means for withdrawing water vapor from said solution in said first flash tank by maintaining a subatmospheric pressure therein, means for conducting said water vapor withdrawn from said solution in said first flash tank into said condenser, means for injecting live steam into said solution and said water vapor in said condenser in order to heat said solution and said water vapor therein substantially to said relatively high temperature, means for conducting said solution from said condenser into said plating chamber, a second flash tank, means for conducting said solution from said first flash tank into said second flash tank, means for withdrawing and discharging to the exterior water vapor from said solution in said second flash tank by maintaining a subatmospheric pressure therein in order to cool said solution therein substantially to said relatively low temperature, and means for conducting said solution from said second flash tank back into said reservoir, the quantity of said live steam injected into said solution and said water vapor in said condenser and the quantity of said Water vapor withdrawn from said solution in said second flash tank being substantially equal.

7. A chemical nickel plating system comprising a reservoir for storing a first portionof an aqueous chemical nickel plating solution of the nickel cation-hypophosphite anion type at a relatively low temperature, a plating chamber for holding a second portion of said solution as a bath at a relatively high temperature, a condenser, means for conducting said solution from said reservoir into said condenser, a first flash tank, means for conducting said solution from said plating chamber into said first flash tank, a conduit connected between said first flash tank and said condenser, means including a steam injector provided in said conduit for withdrawing water vapor from said solution in said first flash tank by maintaining a subatmospheric pressure therein and for discharging said withdrawn water vapor and live steam through said conduit into said solution in said condenser in order to heat said solution and said water vapor therein substantially to said relatively high temperature, means for conducting said solution from said condenser into said plating chamber, a second flash tank, means for conducting said solution from said first flash tank into said second flash tank, means for withdrawing and discharging to the exterior water vapor from said solution in said second flash tank by maintaining a subatmospheric pressure therein in order to cool said solution therein sub- 13 stantially to said relatively low temperature, and means for conducting said solution from said second flash tank back into said reservoir, the quantity of said live steam injected into said solution in said condenser and the quantity of said water vapor withdrawn from said solution'in said second flash tank being substantially equal.

8. A chemical nickel plating system comprising. a reservoir for storing a first portion of an aqueous chemical nickel plating solution of the nickel cation-hypophosphite anion type at a relatively low temperature, a plating chamber for holding a second portion of said solution as a bath at a relatively high temperature, a condenser, means for conducting said solutionfrom said reservoir into said condenser, a first flash tank, means for conducting said solution from said plating chamber into said first flash tank, means for withdrawing water vapor from said solution in said first flash tank by maintaining, a subatmospheric pressure therein, means for conducting said water vapor withdrawn from said solution in saidfirst flash tank into said condenser, means for injecting live steam into said solution and said. water vapor in said condenser in order to heat said solution and said water vapor therein substantially to said relatively high temperature, means for conducting said solution from said condenser into said plating chamber, a second flash tank, means for conducting said solution from. said first flash tank into said second flash tank, a conduit connected between said second fiashtank and the exterior, means in cluding a steam injector provided in. said conduit for withdrawing water vapor from said solution in said secondflash tank by maintaining a subatrno spheric pressure therein and for discharging said withdrawn water vapor and live steam through said conduit to the exterior in order to cool said solution in said second flash. tank substantially to said relatively low temperature, and means for conducting said solution from said second flash tank back into said reservoir, the quantity of said live steam injected into said solution and said water vapor in said condenser and the quantity of said water vapor withdrawn from said solution in said second flash tank being substantially equal.

9. The method of chemically plating with nickel the interior of a hollow. container formed essentially of an element selected from the group consisting of copper,

silver, gold, aluminum, iron, cobalt, nickel, palladium and platinum; which method comprises providing an. aqueous chemical nickel plating solution of the nickel cation hypophosphite anion type having substantially a predetermined composition and characterized by a high plating rate at a temperature within a given range disposed near the boiling point thereof, rotating said container'throughout a given time interval about a substantially horizontal axis, maintaining duringsaid rotation and throughout said time interval said container at least partially filled with said solution, and circulating during said rotation and throughout said time interval said solution from the ex terior into said container and therethrough and back to the exterior, wherein said solution when introduced into said container has a temperature within said given range, and wherein the rate of circulation of said solution through said container is suthciently high to maintain the temperature of said fill within said given range and to prevent substantial departure of the composition of saidfill from said predetermined composition.

10. The method set forth in claim 9, wherein the lower portion of the interior of said container is submerged during said rotation and throughout said time interval in a pool of said solution and the upper portion of the interior of said container is wet during said rotation and throughout said time interval with a film of said solution, and wherein the speed of rotation of said container is sufficiently fast that the composition of said solution in said film does not depart during said rotation and throughout said time interval more than 50% from the composition of said solution in said'pool as a consequence of the 14 chemical nickel plating reaction in said solutionin said film.

ll. The method set forth in claim 9, wherein the lower portion of said container holds during said rotation and throughout said time interval a pool of said solution and the upper portion of said container accumulates during said'rotation and throughout said time interval a layerof hydrogen gas over said pool as a consequence of the chemical nickel plating reaction in said solution, and further comprising venting to the exterior during said rotation and throughout said time interval said hydrogen gas from said layer.

12. The method of chemically plating with nickel the interior of a steel tank; which method comprises provid-' ing an aqueous chemical nickel plating solution of the nickel cation-hypophosphite anion type having substantially a predetermined composition and characterized by a high plating rate at a temperature within a given range disposed near the boiling point thereof, rotating said. tank throughout a given time interval about its longitudinal axis disposed in a substantially horizontal position, maintaining during said rotation and throughout said time interval said tank at least partially filled with said solution, and circulating during said rotation and throughout said time interval said solution from the exterior intosaid tank and therethrough and back to the exterior, wherein said solution when introduced into said tank has a temperature within said given range, and wherein the rate of circulation of said solution through said tank is sufficiently high to maintain the temperature of said fill within saidgiven range and to prevent substantial departure of the composition of said fill from said predetermined composition.

13. Apparatus for chemically nickel plating the interior of a tank formed of catalytic material and having an opening in an end thereof, said apparatus comprising a base, means carried by said base for removably supporting said tank with its longitudinal axis in a substantially horizontal' position and for rotating said tank about its longitudinal axis in its supported position, stationary fixture mechanism communicating through said opening with the interior of said tank and accommodating rotation of said tank with respect thereto, and means for circulating an aqueous chemical nickel plating solution of the nickel cation-hypophosphite anion type from the outside through said fixture mechanism into the interior of said tank and then from the interior of said tank back to the outside during rotation of said tank.

14. The apparatus set forth in claim 13, wherein said fixture mechanism also includes a conduit communicating between the upper portion of the interior of said tank and the exterior for the purpose of venting from the interior of said tank hydrogen gas accumulating therein as a consequence of the nickel plating reaction taking place in said solution in said tank.

15. Apparatus for chemically nickel plating the interior of a. substantially drum-like steel tank including a side wall and an end wall, said end wall having an' opening therein, said apparatus comprising a base, roller mechanismcarried by said base and engaging the exterior of said side wall for removably supporting said tank with its longitudinal axis in a substantially horizontal position, motor means for driving said roller mechanism in order to cause it to rotate said tank about its longitudinal axis in its supported position by friction between said roller mechanism and said side wall, stationary fixture mechanism communicating through said opening with the interior of said tank and accommodating rotation of said tank with respect thereto, and means for circulating an aqueous chemical nickel plating bath from the interior of the outside through said fixture mechanism into the interior of said tank and then from said tank back to the outside during rotation of said tank.

16'. The apparatus set forth in claim 15, wherein said roller mechanism includes a pair of longitudinally spacedapart roller supports respectively engaging said side wall adjacent to the opposite ends thereof.

17. Apparatus for chemically nickel plating the interior of a substantially drum-like steel tank, said apparatus comprising a base, roller mechanism carried by said base and engaging the exterior of the side wall of said tank for removably supporting said tank with its longitudinal axis only slightly inclined with respect to the horizontal so that one end of said tank is only slightly higher than the other end thereof, motor means for driving said roller mechanism in order to cause it to rotate said tank about its longitudinal axis in its supported position by friction between said roller mechanism and the side wall of said tank, a thrust roller carried by said base and engaging said other end of said tank so as to prevent longitudinal shifting of said tank incident to rotation thereof, stationary fixture mechanism detachably connectible in liquidtight relation with said tank and accommodating rotation of said tank with respect thereto, and means for circulating an aqueous chemical nickel plating bath from the outside through said fixture mechanism into said tank and then from said tank through said fixture mechanism back to the outside during rotation of said tank.

18. A chemical nickel plating system comprising a reservoir for storing a first portion of an aqueous chemical nickel plating solution of the nickel cation-hypophosphite anion type at a relatively low temperature, a plating chamber for holding a second portion of said solution as a bath at a relatively high temperature, a condenser, means for conducting said solution from said reservoir into said condenser, a device selectively operable to inject a variable quantity of live steam into said solution in said condenser in order to heat said solution to a variable temperature, a conduit for conducting said solution from said condenser into said plating chamber, thermal responsive means controlled by the temperature of said solution in said conduit for selectively operating said device so as to maintain the temperature of said solution in said conduit substantially at said relatively high temperature, a flash tank, means for conducting said solution from said plating chamber into said flash tank, means for withdrawing and discharging to the exterior water vapor from said solution in said flash tank by maintaining a subatmospheric pressure therein in order to cool said solution therein substantially to said relatively low temperature, and means for conducting said solution from said flash tank back into said reservoir, the quantity of said live steam injected into said solution in said condenser and the quantity of said water vapor withdrawn from said solution in said flash tank being substantially equal.

19. A heat exchange system comprising a reservoir for storing one portion of a processing solution including a liquid solvent at a relatively low temperature, a process chamber for holding another portion of said processing solution at a relatively high temperature, a condenser, means for conducting said processing solution from said reservoir into said condenser, a first flash tank, means for conducting said processing solution from said process chamber into said first flash tank, a source of heated vapor of said liquid solvent, a jet-vacuum pump including a nozzle connected to said source and a suction fixture connected to said first flash tank and a discharge fixture connected to said condenser, said jet-vacuum pump being operated by said heated vapor supplied to said nozzle from said source and eflecting the withdrawal of vapor of said liquid solvent from said processing solution in said first flash tank via said suction fixture and the discharge of said withdrawn vapor and said heated vapor into said processing solution in said condenser via said discharge fixture so as to cause initial cooling of said processing solution in said first flash tank and heating of said processing solution in said condenser substantially to said relatively high temperature, means for conducting said processing solution from said condenser into said process chamber, a second flash tank, means for conducting said processing solution from said first flash tank into said second flash tank, pump means for withdrawing vapor of said liquid solvent from said processing solution in said second flash tank by maintaining a subatmospheric pressure therein and for discharging said last-mentioned withdrawn vapor to the exterior so as to cause further cooling of said processing solution in said second flash tank substantially to said relatively low temperature, and means for conducting said processing solution from said second flash tank back into said reservoir, the quantity of said heated vapor introduced into said processing solution in said condenser and the quantity of said vapor withdrawn from said processing solution in said second flash tank and discharged to the exterior being substantially equal.

20. A heat exchange system comprising a reservoir for storing one portion of a processing liquid containing water at a relatively low temperature, a process chamber for holding another portion of said processing liquid at a relatively high temperature, a condenser, means for conducting said processing liquid from said reservoir into said condenser, a first flash tank, means for conducting said processing liquid from said process chamber into said first flash tank, a source of steam, a jet-vacuum pump including a nozzle connected to said source and a suction fixture connected to said first flash tank and a discharge fixture connected to said condenser, said jet-vacuum pump being operated by said steam supplied to said nozzle from said source and effecting the withdrawal of water vapor from said processing liquid in said first flash tank via said suction fixture and the discharge of said Withdrawn Water vapor and said steam into said processing liquid in said condenser via said discharge fixture so as to cause initial cooling of said processing liquid in said first flash tank and heating of said processing liquid in said condenser substantially to said relatively high temperature, means for conducting said processing liquid from said condenser into said process chamber, a second flash tank, means for conducting said processing liquid from said first flash tank into said second flash tank, pump means for withdrawing water vapor from said processing liquid in said second flash tank by maintaining a subatmospheric pressure therein and for discharging said last-mentioned withdrawn water vapor to the exterior so as to cause further cooling of said processing liquid in said second flash tank substantially to said relatively low temperature, and means for conducting said processing liquid from said second flash tank back into said reservoir, the quantity of said steam introduced into said processing liquid in said condenser and the quantity of said water vapor withdrawn from said processing liquid in said second flash tank and discharged to the exterior being substantially equal.

21. A heat exchange system comprising a reservoir for storing one portion of a processing solution including a liquid solvent at a relatively low temperature, a process chamber for holding another portion of said processing solution at a relatively high temperature, a condenser, means for conducting said processing solution from said reservoir into said condenser, a first flash tank, means for conducting said processing solution from said process chamber into said first flash tank, a source of heated vapor of said liquid solvent, a first jet-vacuum pump in-.

cluding a first nozzle connected to said source and a first suction fixture connected to said first flash tank and a first discharge fixture connected to said condenser, said first jet-vacuum pump being operated by said heated vapor supplied to said first nozzle from said source and effecting the withdrawal of vapor of said liquid solvent from said processing solution in said first flash tank via said first suction fixture and the discharge of said withdrawn vapor and said heated vapor into said processing solution in said condenser via said first discharge fixture so as to cause initial cooling of said processing solution in said first flash tank and heating of said processing solution in said condenser substantially to said relatively high temperature,

17 means for conducting said processing solution from said condenser into said process chamber, a second flash tank, means for conducting said processing solution from said first flash tank into said second flash tank, a second jet-vacuum pump including a second nozzle connected to said source and a second suction fixture connected to said second flash tank and a second discharge fixture communicating with the exterior, said second jet-vacuum pump being operated by said heated vapor supplied to said second nozzle from said source and effecting the withdrawal of vapor of said liquid solvent from said processing solution in said second flash tank via said second suction fixture and the discharge of said last-mentioned withdrawn vapor and said heated vapor to the exterior via said second discharge fixture so as to cause further cooling of said processing solution in said second flash tank substantially to said relatively low temperature, and means for conducting said processing solution from said second flash tank back into said reservoir, the quantity of said heated vapor introduced into said processing solution in said condenser and the quantity of said vapor withdrawn from said processing solution in said second flash tank and discharged to the exterior being substantially equal.

22. The method of chemically plating with nickel a solid body of catalytic material employing an aqueous chemical nickel plating solution of the nickel cationhypophosphite anion type having substantially a predetermined composition and characterized by stability and a low plating rate at a temperature within a first given range disposed well below the boiling point thereof and by instability and a high plating rate at a temperature Within a second given range disposed near the boiling point thereof; said method comprising providing a solution as specified, storing said solution in a reservoir at a temperature within said first range, Withdrawing said soiution from said reservoir and introducing it into a condenser, heating said solution to a temperature Within said second range, said last-mentioned step involving injecting from the exterior live steam into said solution in said condenser, withdrawing said solution from said condenser and introducing it into a plating chamber, withdrawing said solution from said plating chamber and introducing it into a flash tank, cooling said solution-to a temperature within said first range, said last-mentioned step involving withdrawing water vapor from said solution in said flash tank, discharging to the exterior said water vapor withdrawn from said solution, withdrawing said solution from said flash tank and returning it into said reservoir, the quantity of said live steam injected into said solution in said condenser and the quantity of said water vapor withdrawn from said solution in said flash tank being substantially equal, and immersing said body in said solution in said plating chamber.

23. The method set forth in claim 22, wherein said solution is circulated substantially continuously firom said reservoir to said condenser and then to said plating chamber and thence to said flash tank and back to said reservoir, said live steam is injected substantially continuously into said solution, and said water vapor is withdrawn substantially continuously from said solution, and wherein the rate of injection of said live steam into said solution and the rate of withdrawal of said water vapor from said solution are substantially equal.

24. The method set forth in claim 23, wherein said circulation of said solution through said plating chamber is substantially at a first fixed rate by weight, and said injection of said live steam into said solution is substantially at a second fixed rate by weight, said first rate being substantially greater than said second rate.

25. The method set forth in claim 22, and further comprising supplying make-up nickel cations and makeup hypophosphite anions to said solution in said reservoir to prevent substantial departure of the composition of said solution from said predetermined composition 18' in said plating chamber as a consequence of the chemical nickel plating reaction taking place therein.

26. The method set forth in claim 22, wherein said first temperature range consists of the band extending somewhat below about F., and said second temperature range consists of the band extending somewhat below about 210 F.

27. The method of chemically plating with nickel a solid body of catalytic material employing an aqueous chemical nickel plating solution of the nickel cationhypophosphite anion type having a substantially predetermined composition establishing a corresponding predetermined concentration thereof and characterized by stability and a low plating rate at a temperature within 'a first given range disposed well below the boiling point thereof and by instabilityand a high plating rate at a temperature within a second given range disposed near the boiling point thereof; said method comprising providing a solution as specified, storing said solution in a reservoir at a temperature within said first range and at said predetermined concentration, circulating said solution from said reservoir through a condenser and then through a plating chamber and thence through a flash tank and back into said reservoir, simultaneously heating said solution to a temperature within said second range.

and diluting said solution somewhat below said predetermined concentration, said last-mentioned step involving injecting from the exterior a controlled amount of live steam into said solution in said condenser, simultaneously cooling said solution to a temperature within said first range and concentrating said solution substantially back to said predetermined concentration, said last mentioned step involving withdrawing a controlled amount of water vapor from said solution in said flash tank, discharging to the exterior said water vapor with drawn from said solution, and immersing said body in said solution in said plating chamber.

28. The method of chemically plating with nickel a solid body of catalytic material employing an aqueous chemical nickel plating solution of the nickel cationhypophosphite anion type having substantially a predetermined composition establishing a corresponding predetermined concentration thereof and characterized by stability and a low plating rate at a temperature within a first given range disposed well below the boiling point thereof and by instability and a high plating rate at a temperature within a second given range disposed near the boiling point thereof; said method comprising providing a solution as specified, storing said solution in a reservoir at a temperature within said first range and at said predetermined concentration, withdrawing said solution from said reservoir and heating it to a temperature within said second range and diluting it somewhat below said predetermined concentration and introducing it into a plating chamber, withdrawing said solution from said plating chamber and cooling it to a temperature within said first range and concentrating it substantially back to said predetermined concentration and returning it to said reservoir, and immersing said body in said solution in said plating chamber.

29. The method set forth in claim 28, wherein said heating and said diluting of said solution are. effected simultaneously in a condenser by the injection from the exterior of live steam thereinto in said condenser.

30. The method set forth in claim 28, wherein-said cooling and said concentrating ofsaid solution are effected simultaneously in a flash tank by subjecting said solution to a subatmospheric pressure in said flash tank in order to cause water vapor to be given ofi therefrom and discharged to the exterior.

31. The method of chemically plating with nickel a solid body of catalytic material employing an aqueous chemical nickel plating solution of the nickel cationhydrophosphite anion type having substantially a predetermined composition and characterized by stability and a low plating rate at a temperature within a first given rate disposed Well below the boiling point thereof and by instability and a high plating rate at a temperature within a secondgiven range disposed near the boiling point thereof; said method comprising providing a solution as specified, storing a part of said solution in a reservoir at a temperature within said first range, holding another part of said solution as a bath in a plating chamber at a temperture within said second range, immersing said body in said bath in said plating chamber, withdrawing said solution from said reservoir and introducing it into a condenser, withdrawing said solution from said plating chamber and introducing it into a first flash tank, withdrawing water vapor from said solution in said first flash tank and introducing said last-mentioned water vapor into said condenser, injecting from the exterior suflicient live steam into said condenser to heat said solution and said water vapor therein to a temperature Within said second range, withdrawing said solution from said condenser and introducing it into said plating chamber, withdrawing said solution from said first flash tank and introducing it into a second flash tank, withdrawing suflicient water vapor from said solution in said second flash tank to cool said solution therein to a temperature within said first range, discharging said last-mentioned water vapor to the exterior, and withdrawing said solution from said second flash tank and returning it into said reservoir, the quantity of said live steam injected into said solution and said first-mentioned water vapor in said condenser and the quantity of said second-mentioned water vapor withdrawn from said solution in said second flash tank being substantially equal.

32. The method set forth in claim 31, wherein the quantity of said first-mentioned water vapor introduced into said condenser and the quantity of said live steam injected into said condenser are substantially equal.

33. The method set forth in claim 31, wherein said first-mentioned water vapor is withdrawn from said solution in said first flash tank and is introduced into said condenser by said injection of live steam into said condenser.

34. The method set forth in claim 22, wherein both said withdrawal of said water vapor from said solution in said flash tank and said discharge thereof to the exterior are effected by a pumping action that maintains a subatmospheric pressure in said flash tank.

35. The method set forth in claim 27, wherein both said withdrawal of said water vapor from said solution in said flash tank and said discharge thereof to the exterior are effected by a pumping action that maintains a subatmospheric pressure in said flash tank.

36. The apparatus set forth in claim 13, wherein said fixture mechanism includes first and second individual stationary fixtures detachably connectible in liquid-tight relation with the opposite ends of said tank, and said circulation of said plating solution is from the outside through said first fixture into said tank and therethrough and then through said second fixture back to the outside.

37. The apparatus set forth in claim 36, wherein said first and second fixtures are detachably connectible to the opposite ends of said tank substantially in alignment with the longitudinal axis thereof.

38. The method of chemically plating: with nickel a solid body of catalytic material employing an aqueous as specified, storing a first portion ofsaid solution in i a reservoir at a temperature within said first range, holding a second portion of said solution as a plating bath in a plating chamber at a temperature within said second range, circulating said solution from said reservoir through heating apparatus into said plating chamber and therefrom through cooling apparatus back into said reservoir, heating said solution in said heating apparatus to a temperature within said second range, said last-mentioned step involving injecting live steam into said solution in said heating apparatus, whereby the injection of said live steam into said solution heats all parts thereof to the temperature within said second range without heating any part thereof to the boiling point thereof, cooling said solution in said cooling apparatus to a temperature within said first range, and immersing said body in said plating bath in said plating chamber.

39. The method of chemically plating with nickel a solid body of catalytic material employing an aqueous chemical nickel plating solution of the nickel cationhypophosphite anion type having substantially a predetermined composition and characterized by stability and a low plating rate at a temperature within a first given range disposed well below the boiling point thereof and by instability and a high plating rate at a temperature within a second given range disposed near the boiling point thereof; said method comprising providing a solution as specified, storing a first portion of said solu-' tion in a reservoir at a temperature within said first range, holding a second portion of said solution as a plating bath in a plating chamber at a temperature within said second range, circulating said solution from said reservoir through heating apparatus into said plating chamber and therefrom through cooling apparatus back into said reservoir, heating said solution in said heating apparatus to a temperature within said second range, cooling said solution in said cooling apparatus to a temperature within said first range, said last-mentioned step involving withdrawing water vapor from said solution in said cooling apparatus by subjecting it to a subatmospheric pressure, whereby the extraction of said water vapor from said solution is at a temperature well below the boiling point thereof, and immersing said body in said plating bath in said plating chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,072,372 Van der Velden Sept. 2, 1913 2,330,940 Wright Oct. 5, 1943 2,357,415 McManus et al. Sept. 5, 1944 2,377,632 Keller June 5, 1945 2,398,034 Oganowski Apr. 9, 1945 2,532,283 Brenner et al. Dec. 5, 1950 2,587,744 Mallinkrodt, In, et al. Mar. 4, 1952 

9. THE METHOD OF CHEMICALLY PLATING WITH NICKEL THE INTERIOR OF A HOLLOW CONTAINER FORMED ESSENTIALLY OF AN ELEMENT SELECTED FROM THE GROUP CONSISTING OF COPPER, SILVER, GOLD, ALUMINUM, IRON COBALT, NICKEL, PALLADIUM AND PLATINUM; WHICH METHOD COMPRISES PROVIDING AN AQUEOUS CHEMICAL NICKEL PALTING SOLUTION OF THE NICKEL CATIONHYPOPHOSPHITE ANION TYPE HAVING SUBSTANTIALLY A PREDETERMINED COMPOSITION AND CHARACTERIZED BY A HIGH PLATING RATE AT A TEMPERATURE WITHIN A GIVE RANGE DISPOSED NEAR THE BOILING POINT THEREOF, ROTATING SAID CONTAINER THROUGHOUT A GIVEN TIME INTERVAL ABOUT A SUBSTANTIALLY HORIZONTAL AXIS, MAINTAINING DURING SAID ROTATION AND THROUGHOUT SAID TIME INTEVAL SAID CONTAINER AT LEAST PARTIALLY FILLED WITH SAID SOLUTION, AND CIRCULATING DURING SAID ROTATION AND THROUGHTOUT SAID TIME INTERVAL SAID SOLUTION FROM THE EXTERIOR INTO SAID CONTAINER AND THERETHROUGH AND BACK TO THE EXTERRIOR, WHEREIN SAID SOLUTION WHEN INTRODUCED INTO SAID CONTAINER HAS A TEMPERATURE WITHIN SAID GIVEN RANGE AND WHEREIN THE RATE OF CIRCULATION OF SAID SOLUTION THROUGH SAID CONTAINER IS SUFFICIENTLY HIGH TO MAINTAIN THE TEMPERATURE OF SAID FILL WITHIN SAID GIVEN RANGE AND TO PREVENT SUNBSTANTIAL DEPARTURE OF THE COMPOSITION OF SAID FILL FROM SAID PREDETERMINED COMPOSITION. 